The present invention is directed to a system for assisting the learning of a subject. The system is particularly suited for aiding the teaching of a foreign language.
Printed material which is detectable when exposed to light of a particular frequency has been utilized in a number of different applications. For example, U.S. Pat. No. 4,627,819 to Burrows for a "Teaching Or Amusement Apparatus" discloses a printed substrate having some sections with a greater reflectance of infrared light than other sections. The different sections are printed by a particular method in order to reduce the visually detectable discrimination with the naked eye between the two areas.
U.S. Pat. No. 4,588,211 to Greene for a "Machine Readable Document" discloses a document, such as a check, which is made so as to enable a machine to read specific areas of the document and to scan information contained within those specific areas. The specific areas are defined by the printing of a border or other delineation around a predetermined area in fluorescent or similar ink. The scanning mechanism of Greene is sensitive to light reflected by the special ink and is energized to commence scanning upon encountering such special ink during surveying of the documents.
U.S. Pat. No. 3,933,094 to Murphy for a "Substrate Having Colored Indicia Thereon For Read-out By Infrared Scanning Apparatus" discloses a method for making a business reply envelope, by which method one may print a bar code or other indicia for reading by an infrared scanning apparatus while enabling the printing of the bar code in colors other than black or gray.
U.S. Pat. No. 3,471,172 to Bayha for "Scrip For Use With Paper Security Validation Apparatus" discloses the imprinting of a document, such as scrip, with a particular design using different inks. With the Bayha device some of the inks are designed to enable passage of electromagnetic energy, such as infrared light, while other areas of the scrip are printed with other inks which are designed to impede the passage of such electromagnetic energy. Thus, the Bayha documents may be encoded in a machine-readable form.
U.S. Pat. No. 4,604,065 to Frazer, et al. for a "Teaching Or Amusement Apparatus" discloses an apparatus comprised of a substrate having printed intelligence and spatially distinctive areas on the substrate. The distinctive areas are detectable by a hand-held detector which is held adjacent to the substrate and may be sensitive to any of a various number of parameters, such as differences in capacitance, magnetic reluctance, or light intensity in the infrared range.
Thus, the teaching of the art tends toward utilization of non-visible light or other electromagnetic parameters to accommodate interpretation of a printed document by machine reading of some sort.